Mornay Sauce

To make a croque monsieur – or in this case – a croque norvegien, you need to make a mornay sauce. And to make a mornay sauce, you need to trace through two of the most basic sauces: the roux and the béchamel.

Together with hollandaise, velouté, tomato sauce, and espagnole, béchamel is considered one of the five “mother sauces,” – so named, because these five sauces form the building blocks for hundreds of other sauces. They are to cooking what Adenine, Cytosine, Guanine, and Thymine are to DNA.

1. A mornay sauce begins with a roux. To make a roux, melt the butter over medium-low heat in a medium saucepan until it begins to bubble and foam. Once bubbling, whisk in the flour, stirring until the two are well-combined, and the flour is off-white with a nutty smell – about 2 to 3 minutes.

BECHAMEL: A ROUX WITH MILK

2. The roux now becomes a béchamel. To make the béchamel, slowly add 3/4 cup of milk, whisking constantly, until thickened. If it’s too thick, you can always add more milk.

MORNAY: A BECHAMEL WITH CHEESE

3. From the béchamel, we get the mornay sauce. To make the mornay, off the heat, add the salt, pepper, nutmeg, 1/2 cup grated Gruyere, and 1/2 cup grated Parmesan.